Method and apparatus for compensating for the deflection of steel plate rolling mill rolls

ABSTRACT

Disclosed is a crown-controlled roll for use in a rolling mill. The roll is constructed with a sleeve mounted on a mandrel having an axially located bore for transmitting a controlled pressurized fluid medium through radially extending bores into a gap between the mandrel and the sleeve. At each end of the mandrel distinct from the gap, peripheral seals are actuated by fluid transmitted radially from the axial bore. The roll sleeve is constructed with a thickness of approximately 0.15 of the outside diameter of the backup roll. Cams are used to rigidly interconnect the mandrel with the sleeve.

O United States Patent. 1111 ,604, 86

[72] Inventor ErichBretschnelrler 2,826,005 3/1958 Wynne Ill/2 Butlerlch, Germany 2,970,339 2/1961 Hausman 100/102 11 21 Appl.No.- 760,897 1,045,201.11/1912 Shoop 29/113ux [22] Filed Sept. 19,1968 3,196,520 7/1965 Appenzellcr 29/116AD 451 Patented Sept. 14,1971 3,290,897 12/1966 Kuehn 29/115x [73] Assignee SiegenerMachinenbau,G.m.b.II. 3,362,055 1/1968 Bryce 29/113 AD 1 Priority 2 1 29, 1967 FOREIGN PATENTS [3 "many 338174 6/1959 Switzerland 100/170 6021553 1,277,793 9/1968 Germany 29/113AD [54] METHOD AND APPARATUS FOR COMPENSATING FOR THE DEFLECTION OF STEEL PLATE ROLLING MILL ROLLS Claims, 1 Drawing Fig.

[52] U.S.Cl 29/113, 29/148.4, 100/170 511 110.01 "B2111 29/00, I B02c 4/30 Field ofSearch ..29/113, 113

AD, 116, 116 AD, 1 15, 148.4, 901,904;

/162, 162 B, 170, ;241/294, 293; 74/230.16; 72/240, 243; 18/2 C, 2 MT Primary Examiner-Leon G. Machlin flitorney-Ilenry Westin ABSTRACT: Disclosed is a crown-controlled roll for use in a rolling mill. The roll is constructed with a sleeve mounted on a mandrel having an axially located bore for transmitting a controlled pressurized fluid medium through radially extending bores into a gap between the mandrel and the sleeve. At each end of the mandrel distinct from the gap, peripheral seals are actuated by fluid transmitted radially from the axial bore. The roll sleeve is constructed with a thickness of approximately 0.15 of the outside diameter of the backup roll. Cams are used to rigidly interconnect the mandrel with the sleeve.

I N VENTOR ERICH BRETSCHNEIDER ATTORNEY I PATENIEU SEP 1 4 nm METHOD AND APPARATUS FOR COMPENSATING FOR THE DEFLECTION OF STEEL PLATE ROLLING MILL ROLLS BACKGROUND OF THE INVENTION The processing of metal by rolling mills, in a well-known manner, is done in such a way that the rolling pressure is transferred from the rolls by means of screwdowns supported in the roll housings by bearing chocks mounted on journals at both sides of the roll. In this construction it cannot be avoided that the rolls deflect in the middle. The extent of this deflection is a function of the length of the roll, the roll diameter, and the instantaneously exerted rolling pressure.

In order to attain a thickness of the rolled stock which is as uniform as possible and within a close tolerance, each work roll is supported by a larger diameter backup support roll by which the deflection of the work roll is counteracted. The employment of such additional support rolls not only increases considerably the construction costs for the rolling mills,'but also the deflection of the work rolls can only be counteracted within certain limits.

For reducing the construction costs of the rolling mills, it is known in the art to use rolls with roll bodies shaped, so to speak, in the form of a drum, wherein the drum form of the roll body is determined in such a manner that the roll body becomes straight at the rolling mill pass line as a result of the roll deflection resulting from a predetermined rolling pressure, and thereby results in the desired rolling effect. However, this desired rolling effect occurs only when the predetermined rolling pressure is maintained, while with a lower rolling pressure the stock is rolled thinner in the middle than at the borders, and with a higher rolling pressure the stock is rolled thicker in the middle than at the borders.

It is also known in the art to deflect the rolls of a rolling mill toward the roll gap by applying a suitable force to the roll journals in order to compensate for the roll deflection that occurs as a result of the rolling pressure in a direction away from the roll gap. In this case, although it is possible to counteract with comparative accuracy the roll deflection away from the roll gap, it is necessary to provide a special design of the rolling mill with increased costs for its construction.

In fabric treatment lines it is known in the art, for the purpose of creating a uniform pressure, to use rolls which consist of a mandrel or axle and a roll sleeve surrounding it at a sizable distance while pressurized fluid is directed into the hollow space between the axle and the roll sleeve. In this case, the large volume hollow space between the axle and the roll sleeve is subdivided into separate chambers by a multitude of radial walls, and provisions are made for pressuring only that chamber which at the moment lies at the pressure line.

Due to the complicated chamber system and the rotating slide unit used to alternately pressurize and depressurize the chamber system, this roll construction is comparatively expensive and easily subject to malfunctions, and because of the relatively rough operation of a rolling mill, this roll design is not suitable for such an operation.

In addition, the different pressure conditions within the hollow space of such a roll and the large volume of the hollow space would also exclude the use of the roll in a rolling mill roll because it cannot endure the stresses occuring during the rolling mill operation. Moreover, the radial separating walls between the individual chambers are used only for sealing and not supporting because such rolls are constructed to yield in theradial direction.

In another form of the prior art, rolls are formed from a roll sleeve shrunken onto an axle and, for the purpose of internal cooling or heating, between the roll sleeve and axle several channels are arranged about the periphery of the axle. The channels, at each of their ends, empty into a ring channel which is connected by radial channels to a central bore in the axle. Through one end of the central bore the cooling or heating medium is piped in and then it is carried by the radial channels to the peripheral grooves. After circulating, the medium is collected in the annular groove at the other end of the roll and is directed by the radial channels to the central bore where it is carried away from the roll.

This well-known roll construction, although having channels formed between the axle and the roll sleeve, does no more than flush the channels with a fluid medium for achieving a cooling or heating effect.

Furthermore, with respect to this known roll construction, there is no provision of exposing the peripheral channels running in the longitudinal direction of the axle to the action of a high-pressure fluid. Even if high-pressure fluid was to be directed into these channels, there could not occur, as a result, uniform deflection of the roll sleeve into a barrel-shaped form over the length of the roll because the channels adjacent each other are a comparatively great distance from each other, and the fluid is supplied into the channels at their ends so that a nonuniform pressure distribution would occur and, with it, leaky spots would show up at that end of the roll sleeve where the pressure medium is supplied.

SUMMARY OF THE INVENTION The object of the present invention is to avoid the adverse consequences arising from deflection of the roll bodies of rolling mill rolls during the rolling operation and at a comparatively low construction expenditure for the rolling mill. Another object of the present invention is the possibility of compensating for the deflection of the roll bodies during rolling when using conventionally designed roll stands.

In the procedural respect, the present invention essentially consists of employing during the rolling operation a rolling mill having at least one roll into which a controllable highpressure fluid is directed into a gap formed between a roll sleeve and a mandrel making up the roll. According to another characteristic of this procedure, the high-pressure fluid is supplied centrally through the mandrel and is directed radially into the gap.

' Another characteristic of the present invention resides in supplying the high-pressure fluid directly into the gap at'a point half the length of the mandrel, as well as directing the fluid near each end of the mandrel against radial sealing gaskets.

A rolling mill roll for putting this procedure into effect, according to this invention, comprises a mandrel having a flat groove formed on the periphery thereof and extending over the greater part of the mandrel between the mandrel body and a roll sleeve to form a gap; and a pressure fluid channel aligning with the axis of rotation of the mandrel is connected to the gap by radial channels.

According to the invention, the mandrel is preferably provided with an annular groove into which a ring gasket is received and whose inside periphery is impinged with highpressure fluid supplied by radial channels communicating with the axially aligned channel. The annular grooves are formed separate and distinct from the gap between the mandrel and roll sleeve.

Such a rolling mill roll is furthermore characterized by constructing the roll sleeve of steel with a wall thickness of about 0.15Xd, where d corresponds to the outside diameter of the roll body. 7

Finally, a further characteristic of the present invention resides in the provision of cam followers received in the mandrel and which mesh with correspondingly shaped follower grooves formed in the roll sleeve.

These features and advantages of the present invention, as well as others, will become more apparent when the following description is read in light of the accompanying drawing which The mandrel 2 is provided over the greater part of its length with a flat peripheral groove 6 that forms a narrow peripheral gap 7 between the mandrel 2 and the roll sleeve 5.

Completely separated from the peripheral gap 7 and near the ends of the mandrel 2, there are formed annular grooves 8 and 9 into which are received ring gaskets l and 11, respectively.

Coaxially with the rotational axis of the mandrel there is located a pressure fluid channel 12 extending internally from the face of the roll journal 4. A plurality of radially extending channels 13 communicates between the peripheral gap 7 and the channel 12 at a point about half of the length of the mandrel.

From the central pressure fluid channel 12 radial channels 14 and I are located near each end of the mandrel 2. The radial channels 14 communicate with the annular groove 8 at the underside of the ring gasket 10, while the radial channels 15 communicate with the annular groove 9 at the underside of the ring gasket 11.

According to the present invention, fluid is delivered through the central channel 12 to the peripheral gap 7 between the mandrel 2 and the roll sleeve 5 whereby the roll sleeve is caused to change its shape, whereby it, so to speak, assumes the form of a barrel under the influence of the highpressure fluid. In doing this, the extent of the barrel-shaped bulging of the roll sleeve 5 can be controlled in a comparatively accurate manner by regulating the pressure of the fluid so that the various roll deflections arising when various roll pressures occur are equalized.

The high-pressure fluid extends through the radial channels 14 and 15 to the under side of the ring gaskets 10 and 1 1 causing the latter to press in the radial direction toward the inner surface of the roll sleeve 5 and thus prevent leakage of highpressure fluid between the roll sleeve 5 and mandrel 2.

It has turned out to be very useful if the wall thickness of the roll sleeve 5 is about 0.15Xd, where d is equivalent to the outside diameter of the roll sleeve 5 of a new roll.

Surprisingly, it has turned out that a sleeved roll designed in such a manner by the action of the internal pressure on the roll sleeve permits an elastic, barrel-shaped expansion of the latter which is greater than the extent of the attainable elastic prebending of a massive roll in the direction toward the working pressure line of the roll.

Thus, for example, in the case of a massive roll of l,070 mm. outside diameter, an elastic bending by 0.255 mm. toward the pressure line is possible. In contrast to this, in the case of a sleeved roll, according to the present invention, with an outside diameter or 1,070 mm. and 770 mm. inside diameter of the roll sleeve, a dilatation of 0.29 mm. is possible by the application of a pressure of 400 kp/cm. The extent of the attainable dilatation is calculated in accordance with the formula taken from the German Vorlesungen Uaeber Technische Mechanik, Volume III, by Prof. Foppl, page 223 in the following manner:

2r =770 mm. 11:38.5 cm. 2T3: 1070 mm. 13 53.5 cm.

P =400 kp./em.

1 3700 1070 A =77-66=O.29 mm.

Similar conditions exist also in the case of rolls with turned down roll sleeve.

Let us assume that a massive roll has been turned down from a diameter of 1,070 mm. to a diameter of 980 mm. A possible deflection of 0.349 mm. results in this instance.

Compared to this, in the case of a sleeved roll turned down to an outside diameter of 980 mm., a dilatation can be attained which amounts to 0.39 mm.

The extent of the dilatation in this case is calculated by the following formula:

As can be seen from the drawing, the mandrel 2 of the sleeved roll 1 is provided with a vent line 16 to insure that the gap 7 between the mandrel 2 and the roll sleeve 5 is completely filled with fluid. This vent line is hermetically sealed against the outside after the gap 7 is filled.

It can furthermore be seen from the drawing that the mandrel is provided at one of its ends with radial follower cams. The roll sleeve 5 possesses corresponding follower recesses 18 which, when the roll sleeve 5 is pulled over the mandrel 2, mesh with the follower cam 17. Thus, a completely rotation proof connection between the mandrel 2 and the roll sleeve 5 is assured.

By the use of such rolling mill rolls, it is possible to utilize any conventional rolling mill for the production of rolled stock for high quality requirements, especially with great dimensional accuracy. For this purpose, an existing rolling mill needs only the coordination of a source for high-pressure fluid besides the rolls according to the invention in order to be in a position to achieve the bulged dilatation of the roll sleeve equalizing the individual extent of the roll deflection.

In accordance with the provisions of the patent statutes, l have explained the principle and operation of my invention and have illustrated and described what I consider to represent the best embodiment thereof. However, I desire to have it understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

1. A method of compensating for the elastic deflection of a roll employed in a rolling mill for the rolling of steel and made up of an outer steel sleeve mounted on a mandrel and having a continuous peripheral gap therebetween, comprising the steps of:

expanding said sleeve into a barrel shape by the application of fluid pressure into said gap;

regulating the magnitude of said fluid pressure applied to said gap to produce a desired expansion of said sleeve by deformation into said barrel shape;

forming a central fluid conducting opening in said mandrel extending from one end thereof to a predetermined internal point;

forming a plurality of radially extending ports in said mandrel at the approximate midpoint of the mandrel for interconnecting said opening and said gap to pressurize the gap with fluid delivered to said mandrel; and

forming a fluidtight seal at each end of said roll remote from said gap between said sleeve and said mandrel.

2. A deflection compensating roll for a rolling mill employed for rolling steel comprising:

an elongated outer steel roll sleeve for hearing at least a part of the rolling load generated in said rolling mill;

a mandrel having a body portion intermediate journaled ends for mounting said roll sleeve;

said mandrel having a continuous peripheral recess formed over the greater part of the length of said body portion;

an annular groove formed in each end of said body portion of said mandrel;

each of said grooves being distinct and spaced outward from said peripheral recess;

a ring gasket received in each of said grooves;

said recess in said mandrel, said ring gaskets, and said roll sleeve when mounted thereon defining an elongated peripheral gap;

said mandrel having an internally terminating bore arranged coaxially with the rotation axis of said roll;

a plurality of radially extending channels formed in said mandrel for interconnecting said central bore and said gap in a fluid pressure transmitting relationship;

means for feeding fluid to said bore; and

means for regulating the pressure effect of said fluid with reference to varying roll deflections.

3. A deflection compensating roll according to claim 2 further comprising:

fluid-transmitting channels interconnecting said internal bore and said annular grooves for urging said gasket into a sealing relation with said roll sleeve.

4.' A deflection compensating roll according to claim 2 wherein said elongated roll sleeve is of steel with a wall thickness of about 0. l 5 d, where d corresponds to the outside diameter of said roll sleeve.

5. A deflection compensating roll according to claim 2 further comprising cams received in said mandrel; and

recesses formed in said roll sleeve for meshing in a driving relation with said cams. 

1. A method of compensating for the elastic deflection of a roll employed in a rolling mill for the rolling of steel and made up of an outer steel sleeve mounted on a mandrel and having a continuous peripheral gap therebetween, comprising the steps of: expanding said sleeve into a barrel shape by the application of fluid pressure into said gap; regulating the magnitude of said fluid pressure applied to said gap to produce a desired expansion of said sleeve by deformation into said barrel shape; forming a central fluid conducting opening in said mandrel extending from one end thereof to a predetermined internal point; forming a plurality of radially extending ports in said mandrel at the approximate midpoint of the mandrel for interconnecting said opening and said gap to pressurize the gap with fluid delivered to said mandrel; and forming a fluidtight seal at each end of said roll remote from said gap between said sleeve and said mandrel.
 2. A deflection compensating roll for a rolling mill employed for rolling steel comprising: an elongated outer steel roll sleeve for bearing at least a part of the rolling load generated in said rolling mill; a mandrel having a body portion intermediate journaled ends for mounting said roll sleeve; said mandrel having a continuous peripheral recess formed over the greater part of the length of said body portion; an annular groove formed in each end of said body portion of said mandrel; each of said grooves being distinct and spaced outward from said peripheral recess; a ring gasket received in each of said grooves; said recess in said mandrel, said ring gaskets, and said roll sleeve when mounted thereon defining an elongated peripheral gap; said mandrel having an internally terminating bore arranged coaxially with the rotation axis of said roll; a plurality of radially extending channels formed in said mandrel for interconnecting said central bore and said gap in a fluid pressure transmitting relationship; means for feeding fluid to said bore; and means for regulating the pressure effect of said fluid with reference to varying roll deflections.
 3. A deflection compensating roll according to claim 2 further comprising: fluid-transmitting channels interconnecting said internal bore and said annular grooves for urging said gasket into a sealing relation with said roll sleeve.
 4. A deflection compensating roll according to claim 2 wherein said elongated roll sleeve is of steel with a wall thickness of about 0.15 X d, where d corresponds to the outside diameter of said roll sleeve.
 5. A deflection compensating roll according to claim 2 further comprising cams received in said mandrel; and recesses formed in said roll sleeve for meshing in a driving relation with said cams. 